Process for preparing ketones



her from 8 to 16 or the (hC radical.

United States Patent 3,280,147 PROCESS FOR PREPARING KETONES George A. Olah, Sarnia, Ontario, Canada, assignor to The Dow Chemical Company, Midland, Mich., a corporation of Delaware No Drawing. Filed Feb. 4, 1963, Ser. No. 256,112 16 Claims. (Cl. 260-3323) This application is a continuation-in-part of application Serial Number 207,788, filed July 5, 1962, now abandoned.

This invention relates to an improved process for preparing ketones. Specifically, the invention relates to a process for preparing ketones having the formula:

wherein R represents either a phenyl or an alkyl radical, X is either a halogen having an atomic number from 9 to 53 or an alkyl group, n is an integer from 0 to 3, and Z represents either a chalkogen having an atomic num- A preferred sub-genus is that wherein R represents either a phenyl or a lower alkyl group, X represents a halogen having an atomic number from 9 to 53 or a lower alkyl group, and n is an integer from 0 to 3.

The term lower alkyl is used herein to denote an alkyl group containing from 1 to about 4 carbon atoms.

The novel process is conveniently practiced by reacting by contacting a cyclic compound having the formula:

(X).. Z/ With a thiocarboxylic acid having the formula:

RCOSH or with an acyl sulfide having the formula wherein R, X, Z, and n each have the same significance as previously described, and in the presence of a Friedel- Craft-s type catalyst. The thus-formed ketone is then easily separated from the reaction mixture by conventional procedures, such as by distillation.

The preferred temperature for the reaction will vary somewhat depending on the particular reactants being used. Generally, however, the temperature is maintained between about 0 and 120 C.

Friedel-Crafts type catalysts, in general, are operable in the novel process. Specific catalysts that have given "ice fluoride, boron trifluoride-orthophosphoric acid, hydrogen fluoride and zinc chloride.

The reactants and catalysts are employed in proportions of 1 to about 10 moles of catalyst and 2 to about 5 moles of cyclic compound per mole of thiolcarboxylic acid or sulfide, preferably from 1 to 2 mole-s of catalyst and about 4 moles of cyclic compound per mole of acid or sulfide.

The process of the present invention possesses several advantages over that employing carboxylic acids. The novel process results in the formation of hydrogen sulfide as a by-product, which volatilizes readily and escapes from the system, unlike the known process where water is the by-product and tends to react with the catalyst. In addition, where metal halides are used as catalysts in the known process, large amounts of catalyst are frequently required due to halogenation of the acids to the corresponding acyl halides which then function as acylating agents.

Another important advantage of the present invention is that the yields are much improved over those obtained by the known process employing carboxylic acids or anhydrides. While carboxylic acids will efiect C-acyl-ation of cyclic compounds only with difiiculty when Friedel- Crafts catalysts are employed, the thiolcarboxylic acids effect such C-acylation readily under these conditions. Also it is known that C-acyl-ation of cyclic compounds with acid anhydrides results in the production of 1 mole mole of acylated cyclic compound and 1 mole of carboxylic acid per mole of anhydride. When, however, the acylation is effected with an acyl sulfide, there are produced 2 moles of acylated cyclic compound per mole of acyl sulfide, as illustrated by the equation:

As is readily seen, this important difference in behavior of the acylsulfide leads to markedly improved yields over those obtained with the acid anhydride.

The practice of the present invention is illustrated by a series of experiments in each of which 2 moles of a cyclic compound and 0.5 mole of a thiolcarboxylic acid or of an acyl sulfide each of the respective genera previously described, were reacted in the presence of 1 mole of a Friedel-Crafts type catalyst. The reactions were run for a period of several hours, the product washed with water and separated by distillation and the yield calculated. There are shown in Table I for each experiment conducted, the thiolcarboxylic acid or acyl sulfide, cyclic compound, and catalyst used, the reaction temperature, and the yield of product obtained, based on the starting materials employed, and certain physical propexcellent results include aluminum chloride, boron trierties of the product.

TABLE I Product Exp Thlolcarboxyllc Acid Reaction B.P. or

No. or Acyl Sulfide Cyclic Catalyst Temp, M.P., 0. Ref. Index Compound 0. Yield, Name Percent l Thiolacetic Acid Benzene A1013 50-80 41 Acetonhennnn B.P. 202 ,,:w=1,534, 2 BFa 50 34 do 3 BF -H PO4 35-50 40 do 4-.- AlC 50 53 4-methyl acetophenone B.P. 224 5 90 32 dn 6 0 F. 0-15 23 o 7 do Ethylbenzene. A1013 50 40 4-ethy1 acetophenone B.P. 236 8 do Fluorobenzene AlCla c 37 -fiuoro acetophenone B.P. 8283/12 n,, =l.50,

mm. 9 do Ch10robenzene A1013 30 4 chloro acetophenone B.P. 104-106/ 10 mm. 10 fin Bromob m n A101; 90 30 4-bromo acetophenone B.P. 132134/ TABLE ICntinued Product Exp Thiolcarboxylic Acid Reaction B1. or No. or Acyl Sulfide Cyclic Catalyst Temp, M.P., 0. Ref. Index Compound 0. Yield, Name Percent 11 do Iodobenzene 90 34 4-iodo acetophenone 13.11;. 142-144/ 113111. 12 Thiolpropionic Acid.-- Benzene 78 38 Propiophenone B P. 218 13... o Toluene A 108 45 4-methyl propiophenone n =1.527. 14 do F1uorobenzene 85 31 4-fluoro propiophenone B.P. 9092/12 mm. 15 Thiolbenzoic Aoid Benzene 78 56 Benzophenone M.P. 474B 16 do Toluene 90 61 4-methyl benzophenone M1. 5960 17 Diacetyl sulfide Benzene-.. 50-80 78 Acetonhenono B P. 2n2 n =1.534. 18 do Toluene... 80 81 4-methy1 acetophenone 13.1. 224 do O 47 do Ethylbenzene 80 65 44215113 1 acetophenone B.P. 236 Fluorobenzene 85 61 4-fluoro acetophenone 82-83/12 mm... n,,"=1.508. Chlorohenzene. 100 57 -chloro acetophcnone 104-106/10 mm- Thiophene B 20 80 2-acetyl thiophene ,do Furan 0-10 46 2-acetyl tut-an Dipropionyl sulfide-.- Benzene 5080 71 Propionhenrme El. 218 do Toluene 0 58 4-methyl pr0pi0phen0ne n, =1.527. d0 Fluorobenzene 85 67 -fluoro propiophenone 90-92/12 mm... Dibenzoyl sulfide. Benzene 80 81 Benzophenone M.P. 47-48. do Toluene 5O 84 a t-methyl benzophenone. M.P. 59-60- In addition to those compounds specifically disclosed, other ket-ones within the scope of the present invention may be prepared from analogous cyclic compounds and analogous thiolcarboxylic acids or acyl sulfides, such as for example,

I claim: 1. An improved process for preparing ketones having the formula wherein R represents a member selected from the group consisting of phenyl and alkyl radicals, X represents a member selected from the group consisting of a halogen having an atomic number from 9 to 53 and alkyl groups, Z is a member selected from the group consisting of chalkogens having an atomic number from 8 to 16 and the -C=C radical, and n is an integer from 0 to 3, said process comprising reacting by contacting in the presence of a Friedel-Crafts catalyst a cyclic compound having the formula wherein X, n and Z each have the same significance as previously described, with an acylating agent selected from the group consisting of thiolcarboxylic acids having the formula RCOSH and acyl sulfides having the formula R-O H S wherein R has the same significance as previously described.

2. A process as in claim 1 wherein one to about ten moles of catalyst and two to about 5 moles of the cyclic compound are employed per mole of the acylating agent.

3. A process as in claim 1 wherein l to 2 moles of catalyst and about 4 moles of the cyclic compound are employed per mole of the acylating agent.

4. A process as defined in claim 1 wherein R is an alkyl radical, n is 0, Z is the radical C=C and the acylating agent is RCOSH.

5. A process as defined in claim 1, wherein R is an alkyl radical, n is 0, Z is the radical @C and the acylating agent is (RCO) S.

6. A process as defined in claim 1, wherein R and X are alkyl radicals, n is 1, Z is the radical C=C and the acylating agent is RCOSH.

7. A process as defined in claim 1, wherein R is alkyl, X is halogen, n is 1, Z is the radical C and the acylating agent is RCOSH.

8. A process as defined in claim 1, wherein R is phenyl, n is 0, Z is the radical C=C, and the acylating agent is RCOSH.

9. A process as defined in claim 1, wherein R is phenyl, X is alkyl, n is 1, Z is the radical C=C and the acylating agent is RCOSH.

10. A process as defined in claim 1, wherein R is alkyl, 11 is 0, Z is the radical O=C, and the acylating agent is (RCO) S.

11. A process as defined in claim 1, wherein R and X are alkyl, n is 1, Z is the radical -C=C, and the acylating agent is (RCO) S.

12. A process as defined in claim 1, wherein R is alkyl, X is halogen, n is 1, Z is the radical @C and the acylating agent is (RCO) S.

13. A process as defined in claim 1, wherein R is alkyl, :1 is 0, Z is the radical S, and the acylating agent is (RCO) S.

14. A process as defined in claim 1, wherein R is alkyl, n is 0, Z is the radical O-, and the acylating agent is (RCO) S.

15. A process as defined in claim 1, wherein R is phenyl, rt is 0, Z is the radical C=C--, and the acylating agent is (RCO) S.

16. A process as defined in claim 1, wherein R is phenyl, X is alkyl, n is 1, Z is the radical C=C, and the acylating agent is (RCO) S.

No references cited.

WALTER A. MODANCE, Primary Examiner.

JAMES A. PATTEN, Assistant Examiner. 

1. AN IMPROVED PROCESS FOR PREPARING KETONES HAVING THE FORMULA 